The present invention is directed to mechanical devices and, more specifically, to a one-way clutch.
A prior art one-way clutch is constructed as shown in FIG. 6. As shown in FIG. 6, each of a plurality of clutch member spaces 5 between an external rotary member 1 and an internal rotary member 2 is equipped with only one roller 4 as a clutch rolling member. A retainer 7 and a spring 8 are disposed between each pair of rollers 4 so that each spring 8 may push its corresponding roller 4 into the narrower side of the clutch member space 5 while using the retainer 7 as a reaction member. As a result, when the external rotary member 1 rotates in a direction F, the roller 4 is enabled to quickly bite into a cam surface K1 of the external rotary member 1 and a cam surface K2 of the internal rotary member 2 by the pushing action of the spring 8. Thus, when the rotating force is input to the external rotary member 1, the rotating force is output from the internal rotary member 2 with very little delay.
Since, in the prior art, only one clutch rolling member is disposed in each clutch member space, a relatively large transmission load is applied to each rolling member at the transmission time so that the rolling member becomes liable to wear. As a result of the wear, the rolling members are deformed to make the meshing engagements between the rolling members and the two rotary members unstable, and slippage in the transmission may occur between the external rotary member and the internal rotary member. Furthermore, upon repeated acceleration and deceleration of the input side rotary member, the rolling members are repeatedly carried toward the wider sides of the clutch member spaces in accordance with the overrun of the output side rotary member. As the rollers repeatedly impinging upon the springs the risk of deforming or breaking the springs and the retainers increases.